1. Field of the Invention
This invention relates to an optical lens unit, and more particularly to method and apparatus for adhering light-shielding sheets onto transparent bodies.
2. Description of the Related Art
Referring to FIG. 1, in a conventional optical instrument, a light-shielding sheet 2 is disposed between two lenses 1 so as to shield the light outside an effective light-transmissive region of the lens 1.
The light-shielding sheets 2 are made by punching, and have a minimal thickness and a small surface area. The light-shielding sheets 2 are blown one at a time into a net bag (not shown) by a fan (not shown). After a predetermined number of the light-shielding sheets 2 have been collected within the net bag, the net bag is moved to another place for assembly with the lenses 1. During assembly, the light-shielding sheets 2 are individually removed from the net bag, and are put into a lens barrel 3 one at a time.
Some problems are encountered during assembly of aforesaid conventional optical instrument. For example, it is difficult to perform stocktaking and material management of the light-shielding sheets 2, and the light-shielding sheets 2 may be misplaced. Since the light-shielding sheets 2 are lightweight and thin, they are difficult to move using a suction-type apparatus. Conveying is also made difficult by the fact that static electricity is produced on the light-shielding sheets 2 during assembly. Furthermore, since the light-shielding sheets 2 are moved manually or by a suction device, fingerprints or traces of the suction device are formed on surfaces of the light-shielding sheets 2, thereby adversely affecting the light-shielding effect of the light-shielding sheets 2.